There are two major objectives addressed in this proposal. The first is to develop epidemiologically useful tools for estimating cumulative lead exposure and to conduct a pilot case-control study investigating a potential relationship between lead and hypertension. A detailed environmental and occupational lead exposure questionnaire will be administered to a sample of hypertensives who have been subjects of a prior study to confirm the correlation between X-ray fluorescence measurement of lead stores in bone and urinary lead excretion following diagnostic chelation. X-ray fluorescence values will be available for thirty patients and chelation values for approximately fifteen in this group. The predictive value of component questions and of a variety of dichotomous scoring techniques will be determined, using first diagnostic chelation results then X-ray fluorescence results to establish validity. Reliability will be established through repeated questionnaire administration. X-ray fluorescence will be performed on thirty non-hypertensive orthopedic clinic patients who will be selected as age, sex, and race matched controls. The specificity and sensitivity of the exposure questionnaire will be confirmed in this group. A case-control pilot study comparing both lead exposure estimates and X-ray fluorescence values among hypertensives and non-hypertensive orthopedic patients will be performed. This pilot is not intended to produce definitive results but rather to refine study instruments, evaluate adequacy of matching and determine the sample size needed for a future study. It is a necessary first step which would then allow the question of whether hypertensives have elevated body burdens of lead to be addressed and, if so, whether this is predictable in a given individual on the basis of history. A future question of potential widespread health impact is whether therapeutic chelation in hypertensives with increased lead burdens would affect blood pressure control.